At night, try Google Sky Map. It's awesome, provided you can see stars easily from where you are staying(it's much less effective in big cities).
You need Internet connection for Google Sky though
...the OP is asking for offline
Definitely
Adiko!!! You can install a lot classic literatures for free!!! a MUST!
2 Player reactor - if you have another friend with you...on the train, it's a great game to past the time
the Pro version allows 4 people.
I've played this for over an hour with my friend
Bonsai blast as someone has mentioned - very addictive - you can play for over an hour
CopyCat Lite - challanges how good your memory is
- addictive until you lose >_>;;;
Frozen Bubble - exactly like the arcade game...easier to control if you have a optical ball/pad - very addictive - can go for over an hour
Poke a mole - I like poking things...fun for a couple of minutes
Jewellust lite - a cascade/connect 3 in a row type game - very addicting - over an hour of fun
-Phit Droid - a good mental challenge game
-
Words up - if you like finding words from random letters - it's hard
-
shoot U lite - quite fun - lasts about 10 minutes...if you get stump on a level -_-;
-
Toss it - you're require to use trajectory estimation so it's not quite as brainless as it seems
-
ArtfulBits - Aiminesweeper - great classic mine sweeper game.
Here's the appbrain list of the apps
roze's Offline Games
Have fun in Greece
If you're using your phone as a camera, you might want to get a note app with picture note like 3Banana or note everything.