Friday: 35K, including 4K with mom trying to get her back into cycling.
Sunday: 15K in 38 mins, using both bike computer and AllSport GPS. Here's how the two compare:
CatEye Velo 8
This says two things: it takes about 0.025km for the GPS to lock in, and AllSport has a much friendlier calculation for burned calories. No idea which is more accurate, however.