Windshield wiper motors and their worm-gear reciprocating assemblies are something like starter motors and fuse panels. All are pre-engineered packages designed to provide consistent reliable performance, and all of them provide the same performance, whether they're mounted inside of a car or not. The wiper motor's ability to reliably reciprocate (move back and forth) in either a constant sweep or small increments makes it a prime motivator among hobbyists and garage engineers worldwide.
Most modern wiper motors are intermittent, meaning that they use position sensors inside that tell a motor controller where the wiper is and where it should stop. This design makes them ideal for use with the homemade circuit boards and motor controllers popularly used to build robots. The wiper's position sensor allows the computer to precisely control the position of robotic and animatronic arms and legs and automatically bring them back to their original starting position. While a bit bulky for use in small joints like fingers (unless you're building a full-scale version of Optimus Prime), these very high-torque motors can provide power and precision in equal measure for motive joints.
Many robotic applications require some sort of powerful, constantly reciprocating drive assembly to operate legs and arms. One prime example is the spider-type crawler, in which all of the synchronised legs are powered by the same reciprocating assembly. You could also build a robotic "inchworm" by utilising one wiper motor in each of the worm's segments. Synchronising the motors so that two of the segments are always touching the ground and moving forward will allow your inchworm to crawl along the ground just as fast as the motors can push it. You'll need a lateral-control servo or solenoid in between each segment to control side-to-side motion and turning.
Trains are some of the very few wheeled applications that utilise a reciprocating drive motion. Connecting the motor's output arm to a wheel will exactly mimic the piston-drive motion of an old-fashioned steam train. The motor's very high torque should allow you to pull some serious cargo, too. A basic wiper motor running on 16.5 amps can produce about 3.31kg-ft. of torque, and some more powerful units can produce as much as 15.9kg-ft.; the latter is enough to tow a medium-sized child at low speed. You could also use an intermittent-type wiper motor as a powerful servo to operate the control surfaces on very large (1:4 scale and higher) radio-controlled aeroplanes.
If you're looking for a unique styling touch to add classic charm to your home, then you should consider building a Persian-style fan. These air-movers were the ceiling fans of ancient Babylon, and consist of a single flap of cloth stretched on a wooden frame. The frame connects to the ceiling via a large hinge; a servant standing in one corner of the room would pull a rope connected to the fan, causing it to wave back and forth and provide a constant breeze. Tying this rope to a reciprocating wiper motor with a constant 12-volt supply might be just the ticket if you want to live out your Alexandrian dreams but don't have a spare servant available.