Phil's current will grants Will a considerable amount of inheritance, which is equal to, or worth more than, Carlton's portion.
Which is why Carlton always mentions that he hasn't revised his will whenever there is the slightest chance of Phil dying when resolving an episode's conflict.
- This is Jossed I think in one episode. When Carlton learns he's about to get a baby brother, he complains about having to split the inheritance four ways. If Will was in the will, they would have to split it five ways. Of course Phil could have changed his will again in a later episode
The entire series is Will's coma-dream.
The opening credits decribe Will getting "in one little fight" (against several, larger guys) in the rough neighborhood he grew up in. This results in a coma, wherein he dreams about a life far removed from the urban hell of West Philadelphia in the 90's.
The Fresh Prince of Bel-Air
Carlton and Nicky formed an in-universe version of LMFAO
was based on Benny Medina's experiences with the Gordy family. LMFAO consists of Stefan Gordy and his nephew Skyler. Replace "nephew" with "younger brother" and you can almost imagine Will promoting them. Just look at some of the dorky dancing in their videos; it's all Carlton.
The entire series takes place in Heaven, because Will is dead.
(Note: this theory was originally from this BuzzFeed article)
Will actually died in the fight on the basketball court in West Philly. The taxi driver is actually God, who drives a "rare" cab. He takes Will to heaven, where he works out all his issues with his wealthy Aunt and Uncle. Will only sees his mother and father on special occasions, because that's when they come to visit his grave.
There wasn't any Job Offer
At the end of Papa's Got A Brand New Excuse, Will's Father claims he has been offered a job that would put him on the road for lengths of time and would have to cancel the cross country trip Will had been hoping for. The problem is, there wasn't any. He was just making it up so he wouldn't have to tell Will he was leaving again. Considering he never said what he was doing or who he was going to be working for. He made that up as an excuse cause he refuses to accept responsibility for what happened to Will due to him walking out when he was a kid and cause him to be a slightly troubled teenager growing up.
- Pretty sure this was the intended subtext of the scene - that Will's father was flaking out over having to take responsibility for his son or at the very least, being involved in his son's life.
Philip actually is Will's Father.
Considering they have the same skin tone and Will doesn't look anything like his real Dad I wouldn't be surprised if Phil and Will's mother had a one night stand before he was introduced to Vivian that left her pregnant and he never knew and she didn't tell anybody.
- Isn't Hilary older than Will? That would mean that Phil cheated on Vivian with her sister. Maybe Will's mother wanted to have a child but his father didn't so she got pregnant by Phil using artificial insemination. Will's father left when he found out what she did.
Vivian Banks is a Time Lord
Hilary is 21 at the start of the series and Vivian celebrates her 40th birthday in the second season, meaning she could not have been more than 18 when she had her first child. Let's look at what she must have accomplished between dropping out of high school and running off with a guy and the beginning of the series: she splits with the aforementioned boyfriend, cleans hotel rooms to get back on track, earns a GED, goes to college, pursues and ultimately abandons a career in dance, meets and marries Phil, earns a Ph.D., gives birth to Hilary and Carlton, moves out of the shabby flashback apartment, and gives birth to Ashley. After the start of the series, she welcomes Will into the household, gives birth to her second son, Nicky, and changes physical form
Geoffrey Butler is the same person Joseph Marcell played from Remembrance of the Daleks
The coffee shop worker in Remembrance of the Daleks is naturally a resident of England who witnessed the first Dalek sighting on Earth in November 1963. Throughout the following years, he would have lived long enough to have witnessed, either directly or indirectly many events in the Doctor Who television proper. Amongst those events: WONTAN's attack with the War Machines which occurred during the Chameleon's invasion on Earth in 1965, the Yeti sightings in the London Underground of 1966 and later the Cybermen invasion fronted by International Electromatics. Throughout much of the 1970s and 1980s, he would also hear about the various incidents surrounding UNIT and their scientific advisor Doctor John Smith. Due to the consistent alien invasions mucking about in England, Geoffrey Butler decided to move to America and find work as a butler, believing it to be far more safer than living as a butler there than finding a living in England. Geoffrey Butler seemingly inconsistent alignment with the Banks family may be attributed to him being indirectly exposed to the life of the Doctor and in severe need of a psychologist.
Vivian died shortly after giving birth
While she was OK at first, she started experiencing health issues after he ending of season 3 and died. A devastated uncle Phil got together with an old girlfriend (also named vivian) as his way of coping and the entire family was too sad (because of both the death and seeing uncle Phil's reaction) to ever adress the fact.
Trevor's death wasn't an accident
Trevor's bungee jump was rigged to fail. Jazz had a thing for Hilary, but she loved Trevor. Jazz arranged an accident for him, so he can have Hilary all to himself.