Lets talk about the ORIGINAL best indiegame 2008 before indiegames became, like, hip and everyone wanted a slice of that pie man, dig?
Spelunky is an indie action-adventure game created by Derek Yu and released as freeware for Microsoft Windows on December 21, 2008.
I'm salty they changed around the mechanics slightly enough to throw off my muscle memory and making me feel like I wasted $5 last week.
http://spelunkyworld.com/original.html