To get exciting fish, you need to consider (A. The type of fish and (B. The environment.
Some fish are just kind of stupid. Other fish, however, can be very intelligent and inquisitive. Oscars and other cichlids are good examples, although they're more of a tpet for a devoted fishkeeper, which you seem not to be.
The other thing you have to consider is the environment. Even if you have an intelligent fish, how exciting can you expect it to be in a boring bowl or tank? Think about how exciting YOU would be to watch if you were locked in an 10 x 10 room with nothing but a "tunnel" to crawl through.
Fish don't (for the most part) appreciate toys. They appreciate having an environment that mimics their natural one. Give your fish as large a tank as possible...you can get 55 gallon tank setup for about the same price as you'd pay getting a dog or a cat. Keep them healthy with adequate filtering. Provide a sandy substrate, fake or real plants, rocks and driftwood, and maybe some roommates, too! Fish may not be exciting by themselves, but the fun comes from watching them interact with other fish and other things.
In the end, though, you only want to go through this if you actually care. I started out just the same...one fish in a small bowl. The difference is that I didn't think "how annoying," I thought "how sad! This guy deserves better." Without the motivation to take care of them, your fish aren't going to thrive.