how wold i make a program with three games in it without using too much memory?
one of the games i am planning to put in there is pac-man and the second is something simpler like a maze.
the third can be whatever i don't care as long as it works!!

Well, use as many of the same resources as possible. If you want to loose a little accuracy with PacMan then you can use the maze generator algorithm to generate your PacMan levels. For PacMan you can then add a box to the center after generation where the ghosts go when eaten. Then you can probably use the PacMan ghost AI for your 3rd game, but remember that AI will attempt to catch the player! So, maybe a Dog Catching game? Where you're the dog.

that's brilliant thanks I will be sure to use that!!!

Well, you program of course! ehe.

this really depends on how well you want the program to look, what libraries are available, and how well you can program.

You want to keep things small, then i suggest using the home screen - unless you really want the pretty graphics.

Pacman: hit detection on the home screen can be kinda slow, depending on how many active objects there are. by outputting a 128-token string, you can make a whole map on the home screen. then you can divulge the location of something by providing X and Y for this equation: "16(Y-1)+X". this returns the token position in the string a charecter is on top of.

I suggest using only 1 or two ghosts like this.

Maze: mazes are easy to do, just not the generator. if you provide a picture to be the maze, then using Pxl-Test will allow you to do hit detection. do to the amount of staticity in a maze game (meaning mazes dont interact with the player too much), this will likely be one of the least used games, at least in my opinion.

3rd game: well, if your going for a low-memory solution, then make another random number guessing game. however, there are hundreds of these, so theming it or adding a second objective to the game will diversify it.

the only one i see giving you trouble is the PacMan game, as it requires a large amount of skill to make it responsive and fun. i suggest tackling these games one at a time and pondering over Kerm's "Programming the TI-83 plus/TI-84 plus" found here on Manning.