BIXI is that it requires a credit card. That isn't big deal for locals, just be aware that there may be foreign transaction fees for those of you who aren't from Canada.You also have to be comfortable riding a bike in a big city where you'll be dodging cabs, pedestrians, bikes, etc. The BIXI website has all sorts of details on how to use the system and here are some maps indicating the BIXI stations nearest the TIFF Venues.
Before you rent a bike you should check the BIXI website to make sure that BIXI dock at your location isn't full.
On the maps below the venue is marked with this indicator:
We'll start with the Bloor Hot Docs Cinema located at: 506 Bloor Street West
Isabel Bader Theater: 93 Charles Street West
Jackman Hall, Art Gallery of Ontario: 317 Dundas Street West
Roy Thompson Hall: 60 Simcoe Street