Big teamfight ultimates almost always result in this and are commonly referred to as "Dropping the hammer". Dota Cinema's Symphony of Skills series is focused on the numerous awesome moments that occur with stacking Ultimates onto each other at the same time.
The last game of The International 3 between Na`Vi and Alliance was full of these. After a game that seemed to be firmly in Na`Vi's favor, they started pushing the mid rax, and it seemed that Alliance was putting up a weak defense. However, this was actually a ruse; Nature's Prophet was pushing the top lane, Wisp and Chaos Knight were pushing the bottom. Realizing this, Na`Vi tried to TP back en masse, but Puck (as played by s4) Dream Coiled them, interrupting the teleports and allowing Alliance to dispatch two rax for one. Later on, Alliance was pushing hard. Dendi, as a super fed Templar Assassin, tried to TP back to base. Puck was able to Dream Coil him to stop him from going back, but what's special about this is that if you look at replays or pictures, you can see that the interrupt was pulled off in about a fraction of a second before the TP was completed. Alliance won the game with what are being called the Million Dollar Dream Coils. See it here.
Another on from The International 3: At the end of the game between Alliance and LGD, it becomes a flat-out race to get to the enemy ancient first. See for yourself. Tobi Wan's commentary makes it all the more entertaining.
Tobi:You are a maaaaan, Sylar!
Na`Vi vs. TongFu in the TI3 Loser's Bracket Finals. Dendi's Pudge is almost memetic, but was not going very well in Game 3. It looked very clear that TongFu was going to roll over Na`Vi and face Alliance in the Finals as the Pudge gambit had failed. Until Na`Vi remembered they also had a Chen to combo with Pudge with the now-removed "Fountain Hook" strategy, one of which on TongFu's Gyrocopter with Aegis of Immortality caused the match to pull a full 180 and gave Na`Vi their rematch against Alliance in the Finals.
Skeleton King managed to drum up enough support from the other heroes to have them harvest souls and safeguard his body during Wraith Night so that he may be reborn as Wraith King. The cruel, expansionist tyrant of Skeleton King convinced his teammates that he was worth keeping around, when they could have just let him turn to dust and have his kingdom fall to ruin. And now he will stay around forever more as Wraith King.
Just think about Magnus's backstory, an herd of Rhino-centaurs charging an entire army of Evil Poachers with a freaking volcano going off behind them. That's quite literally pure awesome.
Some of you may remember how DotaCinema makes Sven the Butt Monkey by making him the punching bag of every other heroes' skill set. Then they released a humorous trolling video titled "Sven's Revenge" where it looks like he'll finally get revenge for all the shits he got into... only for it to turns out to be All Just a Dream and in reality, he got punked AGAIN by Skeleton/Wraith King. Then when Sven got a new item set... they released a video where Sven recalls all the times he's made into a punching bag, and then proceeds to ACTUALLY kicks ass and making it stick. Ladies and gentlemen, In Memory Of Sven
The International 4's prize pool. Starting of with $1,600,000 and $2.50 added for every bought Compendium (and additional money from buyable Compendium points), the pool was raised by $200,000 in two hours. Considering only Compendiums, that means the community bought approximately 11 Compendiums per second. The prize pool was doubled in 32 hours, and at this moment has exceeded $4,000,000, higher than any ESports prize pool in history. In 3 days. The International doesn't start until July the 18th.
This already impressive amount has since then doubled as is now up to $8,000,000 and counting as of June 1st.
As of June the 27th, the prize pool has reached $10,000,000. Bear in mind that before the The International 4, nobody believed that the TI 4's prize pool would ever reach these numbers. Impressive, indeed.