Cytus α and VOEZ Rhythm games are great for short bursts of gaming. I usually don't have more than 20 minutes before the family interrupts me.
Final Fantasy V on SNES emu for the Four Job Fiesta. I sneak 10-15 minutes here and there when it's quiet at work. I know this game inside and out so I make pretty heavy use of fast forward to get lots done in little time.
Thinking about getting back into NBA Playgrounds 2 Those games are fun and quick. Might as well see if I can win the Raps another title