You can make a really lovely little terrarium out of an old aquarium. Mostly the plants you'd want to use in there would be small tropicals, because the enclosure will make it higher humidity - unless you fill it almost to the top so the plants are more exposed to air circulation. Whenever you water, it will take longer to dry, and there will be no drainage, except the stones you'll put in the bottom.
The nurseries at the big box stores have a nice selection of little tropical plants that would do well in a small terrarium like that.
I Googled "how to make a terrarium" and several of the articles talk about using cactus and succlents but I've seen friends get in trouble with trying to keep them dry enough. I think it's easier to make it a moist environment, and use little tropicals, moss and ferns and tiny ivy for example. There are articles about using tropicals and a moist environment, too.
http://inhabitat.com/diy-how-t...
