I've been collecting the extended universe cards. Skipped Avatar but will pick up TMNT. looking forward to the Star Trek line too.
Lorwyn is pretty cool. haven't bought into yet though.
When I was in school, before smartphones, there was a good two to three year period where yo-yos were the move. All the cool kids had the Yomega Fireball. One time I learned a cool trick and Jen White agreed to be my girlfriend via note.