You know what my favorite thing is? Playing Sivir and having one or more of Karthus, Caitlyn, and Nidalee on the enemy team.

Speartoss at max range? Shield it!
Bushwhack? Shield it!
Peacemaker? Shield it! (that one's a bit trickier)
Ace in the Hole? Shield it!
Requiem? That's the best of all, it gives you a timer!