Any of the USA basketball games since I love basketball. Olympic lifting in the lighter weight divisions, and of course the 100m dash. I plan to watch more of the olympics this year, so I might have new favorites.
I really like the swimming events, and basketball. The coolest Olympics to watch was '92 in Barcelona because our cable company had a package of 3 channels with 24/7 coverage and none of those sappy stories. I wish they would bring that back, especially with the advent of DVR.