Today I checked Heavens Above and found that the ISS was going to be visible and very bright in the sky tonight, so I headed out with the scope a few minutes before it was to appear. A while later I saw a bright spot move across the sky in the right place and direction. I wasn't able to get it in the field of view of the scope, unfortunately. As it moved into shadow in Canis Minor, I decided to look at the moon (always a nice target) and while moving the scope around I noticed another, brighter spot tracing the same path as the first one! Unfortunately I couldn't get that in the scope either.
After I came in to the house I looked on Live Satellite Tracking and figured out that the second bright spot was the ISS, and the first one was space shuttle Discovery!