I had written down that Toronto Games Expo happens biannually, but that's ambiguous -- is it twice a year or every two years? Their about page says:

The Toronto Game Expo (TGE) is the city’s premier event for gaming and pop culture enthusiasts! Held twice a year, TGE unites gamers, collectors, cosplayers, comic fans, and anime lovers for an unforgettable two-day experience filled with excitement, nostalgia, and community.

Also looking up the word on wordnik, I see that there's actually two words that are more specific:

biannual
Definitions from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Occurring twice each year; semiannual.
• adjective Occurring every two years; biennial.

So I think I should use semiannual instead.