There is so many great experiences and things to do when you're high. Personally, I feel everyhing should be experienced high but here are some of my suggestions for things to do when you're stoned.
1) Get outdoors. Visit a park. Get lost in some woods. See nature at it's best. Also make great places to get stoned.
2) Watch great/trippy movies, listen to music, watch good t.v., play video games.
3) Write, read, make music, play any instruments u can.
4) Look at the stars/clouds.
5) Go see fireworks.
6) Go cruising along country roads.
7) Sit around with friends and just talk about crazy shit. It's especially funny to record these conversations and listen to them later.
8) Play funny board games like trivia, outburst, twister, pictionary, etc.
Whatever you do, do it high and have a good time. In every situation is an opportunity for a great experience. All you have to do is find it.