Oh, so many great places to check out.
I'm assuming the Tut exhibit is at the Royal Ontario Museum, so you'll be right at the Yorkville area. Great shopping and eating. If it's reopened, you might like to check out Sassafraz, which is a great restaurant. West of that is The Annex. I love Bloor Street West.
Stroll up and down Church Street
St. Lawerence Market is always good on the weekends, and the neighbourhood is beautiful
The Distillery District is popular
Take a walk along the waterfront
If you want to take a shortish trip on a streetcar, check out The Beaches. Lots of great little restaurants and shops there
Visit Fort York, if you're into something like that
Kensington Market in China Town
Toronto Eaton Centre/Dundas Square
Take a trip up the CN Tower
And most importantly, don't miss the Bata Shoe Museum!