The first race of the weekend is the BMW Endurance Challenge. You can stream the race on IMSA.TV. The TCR class competes in this race and they can be fun to watch. You will see Civics, Audi R5s, Alfas, and Hyundais. It's a four hour race and starts at 1005 MST.
https://imsatv.imsa.com/
Here is a link to a spotter's guide:
http://www.spotterguides.com/portfolio/19_imsa/
The spotter's guide is quite beneficial if you plan to put a lot of time into these races.
The Rolex 24 is televised in Canada on Discovery Velocity. I usually subscribe to it for Le Mans and then cancel. But I see the channel is available to me now (free preview? I'll take it) so I have the PVR set.
Race start is 1235 MST.
If you don't have Velocity, try IMSA.TV, although it might be geo-blocked in Canada if Velocity is televising it. A VPN configured with a Euro proxy should work.