What do you mean?
If you mean competitive, obviously showdown
If you mean vidya, and like, you haven't played played since RBY, just pick up where you left off, because IMO it's a lot harder to go back to older versions you haven't played after playing a newer version, since each generation introduces a whole bunch of streamlining mechanics that are at times agonizing to go without (reusable TMs are a lifesaver when you're too jewish to use them at all if they are exhaustible)
If you mean TCG, i can't help you there
If you mean the anime, running your car in the garage for a while is probably your best bet
