Found this on Curbly, a list of alternative uses for plastic container lids. While some do not seem so practical (not sure I get the garbage bag one), the list does have some uses. Chief among them the non-stick pan scrapers.

    # Sink stoppers: placing a plastic lid over a drain will create a vacuum and keep the water in your sink or tub.
    # Kid coasters: let the tykes monogram plastic lids to keep their glasses from getting mixed up and from sweating all over the table tops.
    # Cupboard and refrigerator drip pans: shove one under your pepper mill to catch the excess pepper that sifts out the bottom. Ditto for honey containers and all those other drippy things in the fridge.
    # Plant coasters: not only will they catch leaks, they’ll prevent rings on your furniture.
    # Non-stick pan scrapers: they’ll remove the yuck without damaging your pan’s surface.
    # Hamburger separators: slip lids between shaped patties before you freeze them, and then when it’s time to thaw them, they’ll be easy to separate.

Read on to see 6 more.