Castle Resorts & Hotels in Hawaii has announced a Summer on Sale promotion with discounts of up to 50 percent at 21 properties from July 1 through Aug. 21. Condominium resorts operated by Castle are located on or near beaches and island attractions. Sample starting rates include $179 per night for a studio and $245 for a one-bedroom, oceanview suite at the Castle Waikiki Shore; $139 for a one-bedroom suite at the Castle Kamaole Sands on Maui; $169 for a one-bedroom suite at the Castle Kiahuna Plantation on Kauai; and $268 for two- and three-bedroom villas and townhouses at the Halii Kai at Waikoloa on the Big Island. For more information, call 800-367-5004 or visit www.castleresorts.com.