The pilot and passengers were on a local area flight in a hot air balloon. Prior to departure, the pilot conducted a preflight orientation for the passengers, which included proper positioning in the basket during landing. According to the pilot, upon departure, the wind was from the south at 5 knots; however, when he returned for a landing, the wind had increased to 10 knots. The balloon's descent rate near the surface was 30 feet per minute. Upon contact with the ground, the balloon basket slid about 40 to 50 feet before impacting a 6- to 8-inch curb. The basket stopped abruptly and fell over. One of the passengers sustained a broken leg during the landing. The pilot's ground crew reported that the passenger was not against the downwind basket side at the time of ground contact. The pilot indicated that prior to departure, he will now require passengers to demonstrate their landing positioning so that he can ensure their understanding.