I'm going to straight up say, that this project has very quickly become a favorite. In fact...some of the globes that were meant for gifts, may or may not be scattered around my home and office. I just couldn't help myself!
This was a fairly inexpensive project. Jars were collected (this was a great excuse to eat those last few teaspoons of jam or honey). The only costs were liquid glycerin, glitter the figures and the tiles we used to raise the figures. For figures we largely used Hero Clix and Lego mini-figures, but I also grabbed one of those "Toobz" of plastic figures you see at Michael's. It was mythological creatures and really came in handy.
Tiny Dazzler in a spice jar:

A pirate and a mermaid in a mustard jar:

Iceman vs. Icicle in a jam jar:

And my Absolute favorite- Iron Man with Tree in a Goya honey jar:

More info, pics and a tutorial (with a bonus ornament project) can be found here:
http://comicaziladies.wordpress.com/2012/12/12/crafternoon-snowglobes-and-ornaments-or-how-not-to-get-glitter-lung/