Whether evening/night biking is a matter of recreation during the shortened, post-daylight-savings fall days or a matter of commuting necessity, you need a bike light. In order to stay prepared for all that the road throws at you, you also need a pump. Both of these devices can mount on the frame, and when combined with water bottle cages, full water bottles, saddle bags, girly pink streamers, etc. they can really begin to take over your sleek, lightweight performance frame, rendering you an unbalanced, wobbling disaster area.
Welcome our friend multi-function. When it comes to the limited space available on bikes, and the desire to keep the frame as light and nimble as possible, less is always more. So why lug around a separate frame pump and bike light when you could mash these two necessary devices into one? Well, because the PUYL that does just that isn't yet commercially available. Hopefully, it will be however, and you can knock one clunky device off your Trek.
The PUYL is an ingenious little concept created by designer Kai Malter Roever. Not only does it combine a bike light and tire pump into one, frame-mountable device, it takes the pump motion that you use for pumping the tire and directs it toward recharging the battery through a manually powered dynamo of some form. Granted, you likely won't need to pump your tire as often as you'll need to recharge the battery (at least we hope not), but there's no reason you can't pump it up solely for power. Heck, point the air chuck at your face and enjoy a little cool down while you're charging up. The PUYL reportedly offers 45 minutes worth of light from just 20 seconds worth of pump action.
Now's where we get to the inevitable disappointment. As great an innovation as the PUYL is, it's still just a concept. However, according to Treehugger, it won a design award at this year's Eurobike and has a patent pending. Given how simple and useful this product could be to the swath of newborn, eco-conscience cyclists, I'd be surprised if a commercial version doesn't show up in bike shops sometime in the near future. Hopefully, the final product will get a less-cryptic name.