RORY: Oh, well yeah, it can be really nice just to stay at home sometimes because you can do fun things that you normally wouldn’t have time for.
LORELAI: Yeah, like play Running Charades, and get out that Slip ‘N Slide.
Running Charades is a charades game played in teams. Each team has a list of titles (of books, movies etc) that must be acted out to a team member, who is then meant to guess what it is, before another team member runs in to guess the next charade. Whichever team finishes all their charades by guessing correctly the fastest wins the game. It was brought out as a board game in 2000, suggesting that Lorelai bought a copy.
Slip ‘N Slide is a children’s toy brought out in 1961. It’s a long strip of plastic, which when sprayed with water, becomes incredibly slippery so that a child can slide right down to the end of it. Safety warning: they are only suitable for children, there have been several cases of teenagers and adults hurting their backs or necks, or even becoming paralysed, while playing on a Slip ‘N Slide. Lorelai’s joke seems slightly cruel in that context.