Spelunky by Derek Yu and Andy Hull: spelunkyworld.com
Trailer by: kertgartner.com
Inspired by roguelikes, Spelunky is a unique platformer with randomized levels, where a challenging new adventure awaits you each time you play. Journey deep underground and explore fantastic places filled with monsters, traps, and treasure. Discover, purchase, or steal items to help you survive. Each playthrough offers new experiences and Spelunky players have enjoyed dying thousands of times to uncover all of the game's secrets.