Which activities make you lose track of time?

My list keeps building, but to give you an idea here are a few that come to mind:

1) A romantic, satirical or funny book
2) Sitcoms/Series (Grey's Anatomy, Prison Break, The Good Wife, Brothers & Sisters, Men in Trees, etc)
3) Softball (playing or watching it)
4) On-line Scrabble
5) Social media (Facebook, Twitter, blogging, G-chat, etc)
6) Catching a good movie
7) Soaking up those first rays after a bleak winter
8) Spending time with friends and family
9) Cooking up a storm to be enjoyed by family/friends
10) Dancing
11) Daydreaming
12) Shoe shopping (this one can make me lose more than a sense of time, my mind has been known to be lost in the process)