Due to Warsaw's spread-out nature, getting around is definitely challenge we all have to confront, and renting a scooter (the motorbike kind, think Vespa) is certainly a more fun, stylish and convenient option than the bus, tram or searching/paying for car parking. One of Warsaw's top scooter rentals, Skutery Centrum are located within walking distance from the train station and offer a large selection of sporty and stylish rides for beginners and experts. Their expert staff will help you pick out the right ride, which you can rent for as few as 4hrs, by the week, or even buy for keeps. Each comes accommodates 2 people, comes with 2 helmets, and all you need is your normal drivers licence to rent one. It's best to book in advance and secure a pickup time as they might be out of the office in the off-season (call the listed number if that's the case).
Note that the same rules apply here as with car rental, in that Americans, Australians and other poor saps whose countries didn't ratify the Vienna Convention on Road Traffic cannot legally drive on their licenses.