I lived in Glasgow for a few years as a teenager and remember it as often having special events happening. Most of the family have moved south now, only some distant elderly relatives left in Glasgow. I would like to visit them with my 5yo son so they can meet him, but it will be a very boring trip for him if that is all we do. So, I thought I might try to find some special event/festival or something which would be a suitably exciting highlight to a long long trip for a 5/6/7yo, which would just happen to have a visit to some boring (to him, not to me) old people in it. So what kinds of things suitable for this sort of age bracket happen in Glasgow these days? This has waited 5 years so can wait a few more months if there is something cool in October/April/whenever (Summer is already fully booked so if there is stuff in July/August it will be 2016)
The Children's Classics Halloween concert with the RSNO at Glasgow Royal Concert Hall is great. Two presenters, loads of people dressed up and lots of fun. There are other similar events throughout the year but if you're here over Halloween then it's worth visiting.
Can recommend lots of other days out for kids of that age but not sure of any other events or festivals at that time of year.