Why is it important to provide toys?
Toys are important because they provide:

~Mental stimulation. Without challenging activities to occupy your rabbit when you're not home, your rabbit, especially a solitary rabbit, will get bored. This could lead to depression and/or excessive destruction. The creative use of toys can extend your rabbit's life by keeping him interested in his surroundings, by giving him the freedom to interact with those surroundings, and by allowing him to constantly learn and grow.

~Physical exercise. Your rabbit needs safe activities to keep her body in shape as well as her mind. She needs things to climb on, crawl under, hop on and around, dig into, and chew on. Without outlets for these physical needs, your rabbit may become fat or depressed, or may create jumping, chewing, or crawling diversions with your furniture.

~Bunny proofing for your home. As is clear from the above descriptions, toys are not just for your rabbit, they also keep your house safe. By providing your rabbit with a selection of toys chosen to meet her age, sex, reproductive status and temperament, you have fulfilled most of the requirements of bunnyproofing your home.

What are good bunny toys?
If you find your rabbit ingesting plastic or cardboard toys, switch to a different type of toy that the rabbit is not interested in eating.
Some good toys to start with:

~Paper Bags and Cardboard boxes for crawling inside, scratching, and chewing. Bunnies like them much more when there are at least two entry points into the boxes. Chris Rosenzweig has some Great Tips on Building Bunny Box Toys
~Cardboard concrete forms for burrowing
~Cardboard roll from paper towels or toilet paper
~Untreated wicker baskets or boxes full of: shredded paper, junk mail, magazines, straw, or other organic materials for digging
~Yellow Pages for shredding
~Cat toys: Batta balls, and other cat toys that roll or can be tossed
~Parrot toys that can be tossed, or hung from the top of the cage and chewed or hit
~Baby toys: hard plastic (not teething) toys like rattles and keys, things that can be tossed
~Children's or birds' mobiles for hitting
"Lazy cat lodge" (cardboard box with ramps and windows) to climb in and chew on. ~Also, kitty condos, tubes, tunnels, and trees
~Nudge and roll toys like large rubber balls, empty Quaker Oat boxes and small tins
"Busy Bunny" toys
~Plastic Rainbow slinkies
~Toys with ramps and lookouts for climbing and viewing the world
~Dried out pine cones
~Jungle gym type toys from Toys R Us
~A (straw) whisk broom
~A hand towel for bunching and scooting
~Untreated wood, twigs and logs that have been aged for at least 3 months. Apple tree branches can be eaten fresh off the tree. Stay away from: cherry, peach, apricot, plum and redwood, which are all poisonous.
~Untreated sea grass or maize mats from Pier One or Cost Plus
~Things to jump up on (they like to be in high places)
~Colorful, hard plastic caps from laundry detergent and softener bottles. They have great edges for picking up with their teeth, make a nice "ponk" sound when they collide, and the grip ridges molded into the plastic make a neat "rachety" sound when rabbits digs at the cap. The caps are nice for human-stacks-on-floor and bun-knocks-down kind of games. Note: Be sure not to choose caps from caustic material bottles (e.g.drain uncloggers, bathroom cleaner bottles) since a residue of the cleaner might remain no matter how much washing off you do