http://www.infoniagara.com/
this site has tons of in and around the area things to do.
depending on how busy you want to be and your interests are you can do the "typical tourist" stuff ie. maid of the mist, dinner or lunch at the skylon tower, fireworks on specific days and times, but then drive further and check out the aero car (really cool if you don't have a height problem) butterfly conservatory, wineries, casino's etc...
here's a list of things from their site.
Attractions
American Falls
Battle Ground Hotel Museum
Bird Kingdom
Botanical Delights
Butterfly Conservatory
Canadian Falls
Casino Niagara
Falls Night Fireworks
Floral Clock
Greg Frewin Theatre
Hydro Power
IMAX Theatre
Journey Behind the Falls
Kurtz Orchards Gourmet Marketplace
Lundys Lane Historical Museum
Minolta Tower
Murals of Welland
National Helicopters
Niagara Glen
Niagara Grand Dinner Theatre
Niagara Greenhouse
Niagara Helicopters
Niagara in Winter
Niagara on the Lake
Niagara River
Nightly Illumination
Nightmares Fear Factory
Oakes Garden
Oh Canada Eh? Dinner Show
Pen Centre
Queen Victoria Park
Reg's Candy Kitchen
Ripleys Believe it or Not
Skylon Tower
Souvenir City
The Buttery Restaurant & The Henry VIII Feast
The Old Scow
The Welland Canal
The Whirlpool Aero Car
Whirlpool Jet Boat Tours
White Water Walk
Willoughby Historical Museum
Winter Festival of Lights
Zooz