House-touring provides the ultimate in snooping. But taking part in the annual Lafayette Square Spring House & Garden Tour is far more satisfying than merely peering into strangers' medicine cabinets. In addition to the main tour attraction, this two-day event offers a variety of activities (which this year included a concert, vintage "base ball" and an antiques fair). More important, the weekend provides a glimpse into the city's revival. The late-nineteenth-century homes on display have been beautifully restored and maintained, showcasing St. Louis' former grandeur and the hope and splendor of today.