August is dominated by the Edinburgh International Festival (high culture in the main) and the Fringe (mostly comedy). There’s also lots of live music to be had.
Full details of the Festival can be seen here:
And the Fringe is covered here:
There are good cinemas at Fountainbridge (on the route of both the number 1 and 35 buses), which also boasts an Imax.
There is also the Omni at the top of Leith Walk:
And the Ocean Terminal:
It’s a good idea to check out The List magazine, which has comprehensive Edinburgh / Glasgow listings:
See the online version here:
A night out in Glasgow is feasible with the last train at around 11.30pm.