This impressed me a lot, it's very slick:
GMail managed to look into this restaurant confirmation email and see that it referenced an event at a specific time, so it created a link to add to my Google Calendar!
Following the link to their website reveals, however, that reservations are done through some third-party widget that's not OpenTable.
It's a shame that restaurants in Ottawa are fracturing their reservation systems across several providers like this, just like online classifieds for the city are fractured across Kijiji, Craigslist and UsedOttawa, reducing their utility for everyone. Restaurant reservations are the sort of service where these third-party hosted reservation service providers can hugely benefit from network effects. Once one service reaches a tipping point (like it seems OpenTable is achieving in some US cities), it will enable the creation of location-aware mobile apps and a whole bunch of other useful services for finding restaurants around you.
It seems to me that as a restaurateur, you'd have see huge benefits from going with a large provider that's essentially advertising your restaurant for you by publicly listing availability of tables. You'd want to go for the dominant service that could offer this, which hasn't (yet?) happened with OpenTable in Ottawa...