Weekend vs. Weekday

It's going to vary. I personally play a regular weekly game on Monday nights and DM a regular game on Sunday afternoons. If available time manifests, I play one-shot AL games on Saturday afternoons or evenings.

I also know the local hobby store where I play has every table full in advance for regular game play on Wednesday nights with Tuesday and Thursday nights filled 75% of the time lately. Due to several scheduling conflicts at the store, we were asked to move our regular game night twice before settling in on Monday nights.

It depends upon the group.

The 5e game I play in runs on Thur evening. 6pm-10pm. Primarily because that's what works best for the DM. He can't make it Fri/Sat/Sun.

The group I play PF with meets Sunday evening. 6pm-11pm. In this case it's what fits best for most of the group.

It all depends on everyone's age and place in life. Weekends worked better when we were kids and young adults (and didn't have families), weekdays work better now that we are older and have family commitments. Fridays work particularly well, as we're not eating into a weekend day and competing with other activities, but we have a little more flexibility to go a little later if need be since we don't all have to be at work in the morning. That said, that works for us now but in earlier days when people were single, many players wouldn't have been willing to do Friday nights because it was the prime social night of the week.