It is indeed a MacBook. My Late '08 did the exact same thing on occasion. And I never really linked it to any one thing. Though after doing a fresh install of OS X on to a new SSD, it did eventually go away.
As for the time it takes, what sleep does by default on a notebook with OS X is that it actually saves what is in RAM to the hard disk so if the battery dies, or is removed, it will be able to restore what you are working on (think hibernate in Windows). The issue with this is that it can take a long time to write 4-8GB of data to a hard disk. This is greatly diminished with an SSD, but is still there.
It can be disabled however, and go to sleep almost instantly with a terminal command.
Code:
sudo pmset -a hibernatemode 0
I had mine set this way for speed, and it was usually plugged in or had a decent charge when sleeping and being moved anyway that it wasn't ever an issue. I'd always save my work first too.
The display coming back on is usually something needing to be done or something waking it quickly, could be a wireless device, bluetooth, some pice of software, etc. It can be difficult to find. As I said, mine went away with a clean install. But it hadn't done it much before Mavericks, or maybe Lion. Anything before that was always fine.