What's the 'coolest' mechanic/combo you've encountered?

[MΛRCUS HΞLIUS]

One of my favourite ones is a cycling deck with Zenith Flare.
Whenever someone can get Bolas Citadel to go off that's always fun to watch.
A combo I can't get enough of is Exquisite Blood + Marauding Blight-Priest.

Oh, and any red deck going off and winning turn 2 or 3.

[Winter Wolf]

Not a combo player myself per se though I did love KiKi Pestermite back in the day because it was so brutal (that was before they sped it up with Splinter Twin.) Also fun is Zealous Conscripts + Kiki, Restoration Angel and Kiki, etc.

I am big fan of Crystal Shard and ETB creatures like Mulldrifter/Reveillark. And the whole Reveillark-Body Double combo is cool if you want something with 5 parts (not good but fun though it instawins once you assemble it).

I love synergistic decks that don't need any one combo to win. (Aka Midrange) and Reanimator is often a fun way to build that kind of deck.

[loon_93]

Bolas' Citadel + Aetherflux Reservoir + A bunch of Explore creatures to filter out lands.