Personally I like to do my side coding project in the evenings. I find that if I do it in the morning it's too "all consuming" (I'll end up working on it to the exclusion of my main work.) For me morning/early afternoon is my prime coding time so it feels right to devote those hours to my job. I concede that the weekday side project code won't be the most amazing ever, but it's something and it's moving me forward.