You don't say whether the glass has straight and/or exposed edges, but on my table which has both, I found a roll of wallpaper (water-resistant) that I really liked, cut a sheet to wrap around the glass like gift-wrap, and taped it to itself underneath. It lasted a couple of years (without little children around) before it was so ratty we had to replace it with a new sheet.
If wrapping around the edges doesn't work, you could still cut wallpaper to fit (or maybe try a non-woven fabric like ultrasuede, or placemats), and use double-sided tape or carpet tape to hold it to the glass. If you have to custom-cut (to fit an oval, for example) you might do well to cut two or three pieces at the same time so you can replace an old one when it no longer looks good. Or make a paper pattern that you can store for use later.
You may end up with adhesive residue to clean off the glass at some point in the future, but maybe that will come at a less hectic time in your mothering career. And I've found that a thin film of cooking oil left on adhesive overnight is a great, non-toxic way to soften it, then rubbing dry Bon-Ami kitchen cleanser into the goo rolls it right off in little dry crumbs, and leaves the glass clean.
