I like Puerto Lucia. There's always something going on in the marina itself most of the year, though it's generally fairly low-key until about November, when "the season" starts and people start either prepping their boats for cruising east to Central America, or gearing up for the local sailing season with its warmer, sunnier weather and southwesterly winds.
The marina hosts a sailing club, which has sailing courses especially for children and teenagers. They have dinghy races most weekends during June through September, which start at the launch ramp right in front of the med-moored sailboats. Hang out on your own deck and watch them try to sail along the fairway in too-light wind, eventually giving up and getting towed outside the breakwater by grabbing on to the back of the committee power-dinghy. There are a few larger sailboats with adults aboard, that sail on weekends out of Marina Puerto Lucia and the nearby Marina Salinas; I think there may some mild rivalry between the two yacht clubs but I haven't eavesdropped on the conversations enough to know for sure. And, of course there are always small sportfishing boats for hire.