A day with no homework or assignments hanging over my head, making me feel guilty while I procrastinate. A day when I wake up and find find some sort of delicious drink in the fridge (orange & mango juice, coke, etc), or chocolate custard, or both. When that happens, I know it's going to be a good day.
A great day is when that that happens and I get to climb random stuff, just to swing around or whatever. God, I love climbing stuff.