Tired of your steady old bicycle? Then take a look at these six crazy concept bikes! You can fall in love with everything from "The Ride," a $3,000 bicycle with a "continuously variable planetary drive" inspired by Leonardo Da Vinci's designs, to Cardboard Bike, a $30 bicycle intended to be so cheap as to deter theft. Most of these aren't actually on the market, and some, like the bike with square wheels (pictured here), aren't likely to ever hit mass production. Still, the prototypes make for interesting bike dreams.

Those who commute distances too far to bike can check out the seven best electric scooters. I think my favorite is the IKOO, pictured below, partly because it looks sort of futuristic, and partly because it costs just $995. While like the IKOO, some models are already available for purchase, others are still at the prototype stage — so you may have to wait a while to get the scooter of your dreams.

Need more power? Then study this roundup of thrifty motorcycles and scooters which, although not electric, will still save you money and the earth CO2 emissions. Salon's Sam Whitehead put together the list, and leads off his article with this important reminder: "First of all, you should get an actual motorcycle license (you'd be surprised how many people forgo this major detail) and definitely look into some sort of training." After that, you can get out of your gas-guzzing four-wheeler and hit the road!

^{Top photo by vrogy via Wired; bottom photo of IKOO transporter via Treehugger.}