Typhoon Lagoon is older than Disney's Blizzard Beach, but it is still a very fun park and there is lots to do. I actually recommend Typoon Lagoon over Blizzard Beach if you have problems walking up steps. To get on almost all the rides at Blizzard Beach you have to walk up a bunch of steps.
One of the coolest features of Typhoon Lagoon is it's snorkeling pool. You can snorkel across a huge fresh water tank filled with real sharks and tropical fish.
Then of course is the lazy river and the wave pool. For some reason everyone feels the urge to scream every time the wave is generated. Seriously, it shows up like every 3 minutes and people never get tired of doing it.
The best ride there was is the newest ride at Typhoon Lagoon, called Crush'N Gusher. It has three lines, each with different tracks to slide down.
The best tip I can give is to purchase the refillable sports cup.It costs only $10 which for a group of 2 or more, it was worth it if your there all day. They have several soda stations throughout the park that scans the cups and lets you fill them up.