1) Save dryer lint in a large coffee can and use bits of it as fire starter (yes, there's actually a way to benefit from the lint's combustability). Small amounts of dryer lint can be used when starting a campfire, when using the outdoor barbeque grill (in place of lighter fluid), or when starting a fire in the fireplace. And here's a tip I learned from a Boy Scout: the tighter you roll the lint, the longer it burns. Dryer lint is also incredibly light and easy to pack (compacts down to virtually nothing) for backpackers who need to carry some sort of fire starter with them.
2) Use dryer lint and old candle stubs to make great little fire starters that can even be used as gift items. Fill each section of a cardboard egg carton with dryer lint (it must be a cardboard egg carton rather than a styrofoam one). Melt wax from old candles in a double boiler. Carefully pour the melted wax over the dryer lint until the egg carton sections are full. Let dry. Cut each section apart. Use the firestarters instead of kindling by simply lighting the cardboard.
3) Use dryer lint to pad small items being sent through the mail.
These ideas come from Deborah Taylor-Hough in stretcher.com. REMEMBER, dryer lint is EXTREMELY flammable. Be sure to clean your dryer vents often, esp if you use any type of fabric softener.