Megamix is really good, bought it recently.
But some remixes miss vocals and some minigames have horrible voice acting when the games audio output is set to English, so one should change the output for those to Japanese.
You can also play all minigames with friends if only one has the game.
For short durations I also recommend Smash Bros, where you can play some short matches online, if you happen to be somewhere you have WiFi.
The duration of a match caps at 5 minutes so you won't spend too much time there except you really want to beat some jerk who uses characters like Rosalina, Yoshi or Bayonetta to teach them a lesson...
Some people might also like the professor layton games, where you can solve a puzzle and continue the next time you play.
The presentation of those is always quite good, even if the plot twist at the end of the story is always bs, there is no exception to this.
Even the crossover pulled something out of its *** at the end to justify the story and that was the best layton game so far imo as it had Phoenix Wright in it even though the court sessions weren't as good as the ones found in the main series.
i own and played all of those so I assure you it is true.