When it comes to wide-angle lenses, landscapes are usually the first subject that springs to mind, but there are a few other subjects which work quite well with the distortion wides create. Obviously, you need a wide-angle lens or you can use the wider end of your zoom lens if you don't own a wide-angle lens. For something a little more creative, try using a fish-eye lens but the results won't be something everyone likes so use with care.
If you grab a wide-angle lens for portrait work you can have a lot of fun distorting parts of the person you're photographing so they appear larger/smaller in frame. By working from a low position so you're looking up at your subject, you'll increase the size of their feet and lengthen their legs in full length portraits while shoulder/head shots will exaggerate your subject's forehead and chin area. Due to them exaggerating size they will also make a person appear higher off the ground than they are if you shoot up at your subject.
Change your point of view so you're shooting down and their eyes will look like they're bulging out of the image and their nose will look huge while the rest of the body shrinks away to the bottom of the shot. It's not a technique you'd use on everyone, someone who has a particularly large nose probably wouldn't appreciate it (unless they ask!), but applied to the right situations you can create portraits with a unique look and feel.
If you don't think wide-angle lenses give you shots that are amusing enough, pick up a fish-eye lens which, because of the barrel distortion, magnify what's in the centre of the shot while the edges of the image appear curved.
If you use a moderately wide angle lens you can shoot portraits that don't distort the subject, but do still increase the size of objects that are closer to your lens. This makes them great for photographing children or even adults on swings as they'll help exaggerate the movement as they swing towards your lens.
If you stand in a forest with a wide-angle lens and shoot up towards the canopy you can make it look like each tree is reaching for the centre of the photograph, from all different directions even though in reality they're in lines. This is because the wide-angle lens has caused the usually straight verticals to converge, which is usually something photographers try to avoid, however photographers can use the effect to help them create more interesting shots sometimes.
Similar to the above example, converging verticals don't always have to be avoided by architectural photographers either as by shooting close to a building with a wide-angle lens, you can exaggerate the height of the structure. However, it can make it look like the building will topple over backwards so it won't be everyone's cup of tea. You could try cropping in to the building as well as using a wide angle lens to give the impression the building's so tall that it can't fit in the frame.