bunnies like to do the following things:
~ grab something and toss it
~ find hiding places
~ dig
~ destroy things (usually goes hand-in-hand with digging - mine dig at cardboard boxes all the time)
~ chew things
~ forage for food/treats
~ run around/do "bunny 500s"
if you scroll down to the bottom of this page of my website -
http://www.hurricanesleucisticfriends.com/for-da-bunnies.html (just past the youtube videos) - there are some toy ideas for bunnies and even a link to my tutorial on how to build an agility course for rabbits
anything made of hard plastic that they can pick up and toss (baby keys and some sizes of whiffle balls), tend to be very popular (stay away from soft plastic "teething" toys for infants, though). tunnels of any sort and castles/mazes made from cardboard boxes (or just a large, plain cardboard box) are also great, as are old phone books.
you can also build a "dig box"... depending on your bunny's size and where you plan to use the dig box (ie mess is more of a concern for an indoor toy), there are a variety of things that can be used as the base for the dig box - a large disposable aluminum roasting pan, a dish tub, a rubbermaid style storage bin, etc. you can fill it with dirt, shredded paper/newspaper (stay away from the glossy colored pages of the newspaper though), wood pellets, etc.
you can take the cardboard tubes left over from paper towel/toilet paper rolls (assuming they don't have glue still stuck to them) and stuff them with hay and a few little pieces of fruit (preferably stuff with a strong smell) to make a cheap foraging toy (remember, fruit should be limited to 1 tsp per 2 lbs body weight per day at the most).
