If you’re lucky enough to score an invitation for a weekend at the summer home of friends (or friends of a friend, or seasonally strategic acquaintances), it’s in your best interest to make it worth their while. Thankfully, being a charming houseguest is pretty simple. The golden rules are: Be nice, tidy up after yourself, offer to help out in the kitchen — and come bearing gifts. The ideal present is one that can be enjoyed over the weekend, and the weekends to come that you’re invited back for. Scatterbrains will appreciate utilitarian goods like stylish Turkish towels and fancy sunblock, while the practically minded (who no doubt already have all that stuff, immaculately arranged in the hall closet) will be delighted with whimsical thingamajigs and games. Think of the offerings here as investments in future fun.