Things to do downtown Toledo
Toledo is one of the cities that has been reviving its downtown in the past few years... successfully! There is the Mudhens baseball stadion for the sports fan, for the hungry lots of fun places to eat with certain cultural peculiarities: e.g. Tony Packos, Easy Street Café and several great restaurants at the Docks downtown (afterwards take a nice walk in the Owens Park along the river).
The Toledo Zoo is also quite nice and big (and features open-air concerts in its amphitheather in the summer), the Museum of Art (with a world-renowned glass exhibit) is also worth a visit. If you want to shop for some glass (which would make sense in the "Glass city" that Toledo is often called), I recommend the Libbey Factory Outlet also located downtown.

Fun at Lake Erie
Just one hour east from Toledo you'll find one of the largest and coolest amusement parks "Cedar Point" in Sandusky. They keep breaking world records with speed, height and inclination and just really crazy creative rides (a lot of them are built by Swiss companies!). My favorite is the "Raptor", which includes several loops and you ride with your legs hanging down. If you want to be thrilled, ride the Millenium Force (hold on to your head and neck!). Unfortunately, I did not get to ride all the funky new coasters built after 2002, but they look really cool (get a taste on the cedarpoint.com website). They have several water rides in the park, but if you need a real cool down there is also an entire waterpark "Soak City" right next to it or if the weather doesn't play along the indoor water park Castaway Bay.
Also fairly near are a few interesting Islands such as Put-in Bay and Kellys Island both with interesting history and beautiful nature to enjoy an easy vacation near the water.