An odd friendship between Kent and Bunky. Kent's a homophobe, Bunky's openly gay. The two become best friends in the house, Kent even lets Bunky sleep inside the Head of Household room.
The twins joining up in Big Brother 5 US.
In Big Brother 9, the houseguests had a food challenge where they had to make a gravy river to the food groups they wanted. They all actually put aside their differences and were working together for the common goal of getting beer and the right food groups - and this was one of the most argument prone houses in the game.
During one of the Veto competitions in Big Brother 13, every participant recieved a prize (ranging from the Power of Veto to non-beneficial items) and could swap their's with those of the previously eliminated contestants. Shelly (who was on the block) was eliminated first and received the POV, and Jordan was elminated second and got 24 hours of solitary confinement and a call from home. She swapped with Shelly, but not because the latter was on the block. It was soleyl because Shelly would get a call from home and be able to talk to her young daughter.
Big Brother 14 Jen and Danielle talking about Jenn's coming out. Heck, for that matter, homosexuality in the house has always been treated rather well - there have been gay people in the house but almost nobody's ever gone out on them for being homosexual.
Anyone who is more familiar with recent season may find it shocking to go back and see the big deal that was made about Bunky's coming out.
Donny in Big Brother 16 saving Jocasta from the block in Season 16 by using the Veto, stating that she should have to face eviction as sick as she was.
Big Brother Aus:
Bradley, the only nerd in the house for the Season 9 revival so far, gets instantly loved by all the women in the house. They all even go "Awww" when they see him on screen.
While the real intention is to win a challenge for Surly, Zoe really opens to up to Sarah in bed about her fears of the second house (which they don't know is fake currently) as Sarah calms her down and gives her a good hug. Some time after that, Zoe gets her reward from Surly in the diary room. The dinner she missed out on last week after being forced to say yes to having Ray take her place in the captain's corners.
The show's treatment of Josh after he left the house because his brother had died. They stopped live updates, cancelled the current challenged and cancelled the sunday eviction to air a dedication episode to him. Along with that they donated the funds from the (now closed) voting lines to The Salvation Army which Josh and his family supported.
Likewise the housemates' goodbyes to Josh are very heartwarming.
The producer's have always been touchy about death close to housemates, like when they cancelled the Egg Sitting task after finding out one of the housemates had a miscarriage.
Delilah's "eviction" from the house in which she got a family chosen for her by the housemates. Upon leaving through the door, she got taken by a ninja. When the doors closed, the ninja was revealed to be the earlier evicted Stacey who had been with Delilah for most of her time in the house. The family chosen for Delilah The Bradleys were also there to take her.
Benjamin's win which hit its climax when he proposed to his boyfriend Ben (yes they have the same name) live. And Ben said yes!!!
Big Brother Canada:
When Andrew's twin brother came in to say hi to him.
From BBC2, during Week 3 when Ika was up on the block against Heather, before the eviction vote, Ika put aside her Alpha Bitch tendencies (albeit until the check incident), built a pillow fort, and apologized to Heather for bullying her.
And even then, after the cheque Sadistic Choice, Ika delivered most of her Alpha Bitch attitude towards the first five - especially Kenny, Andrew, and Sabrina.
BBC2: Kenny coming out to Sarah during the campout reward. It was very easy to see that Kenny lying about his being gay was really affecting him on an emotional level.