Ugh. Cycling. We've got cars now people, which means that you don't have to pedal your butt off to get from place to place. But if you absolutely insist on punishing yourself like that, consider upgrading your bike with this trailer, which can give you an assistive boost whenever you need it.
I don't know if it's entirely fair to call the Ridekick a "trailer." Like, you hook it up to your back wheel and it trails you on your bike, so that part is right, but you don't pull it. Instead, it pushes you. Inside the Ridekick is a 500 watt motor (just under one horsepower) along with a twelve amp-hour rechargeable battery plus spare room for groceries and whatnot. A handlebar-mounted control cable lets you adjust the throttle as you see fit, and with a top speed of about 20 mph and a range of up to 12 miles, you may never have to pedal again. And if you're one of those crazy people who actually likes pedaling, the Ridekick can be used as a hill assist, augmenting the work you're already doing and making sure that you don't kill yourself.
At about $700, the Ridekick seems really freakin' expensive, but it's still cheaper than all but the very lowest-end pure electric bikes. Plus since the Ridekick is easy to attach to your existing bike, and even easier to remove, you can still keep riding the bike you know and love and only add on the electric motor when you want it.