Best activities to do during a chess tournament

1. Eat well

2. Go swimming

3. Sleep till late morning

Please continue the list

1. Make new friends. If there are teams playing, get the handsomest guy, prettiest girl on your team to make friends on other teams and ferret out any new tricks they plan to pull (Hey, Severn's team is gonna play the Orosov Gambit against 1 e4 e5.  What's that?).
2. Relax between games, especially if you have 3 or more in the day: starting games feeling refreshed is a key.  Except for a brief reminder of opening moves, you're not going to learn enough chess by cracking open a book to influence the rest of your day!

3. An exception to relaxing: Go out of your way to meet and talk to any masters/grandmasters who are available who happen to be at the tournament. If they're running an impromptu endgame, etc. demonstration, pay attention!

4. Make yourself known to local tournament directors, people you learn run clubs, etc.  At some point they may become useful to your progress in chess.

Pay particular attention to the women's games and socialize with them, encourage them without being patronizing.  Especially if they're hot.

4. Make new friends

5. Take pictures with other chess players

6. Talk about the games while having dinner