The Futurological Congress by Stanislaw Lem

A giant of twentieth-century science fiction' Guardian' This Room Guaranteed BOMB-FREE. From the Management 'Hapless cosmonaut Ijon Tichy has been sent back to earth to attend the Eighth Futurological Congress in smog-bound, overpopulated Costa Rica, holed up with an assortment of scientists in a luxury hotel (fully equipped with tear gas sprinklers in case things get out of hand). But when an unfortunate incident occurs involving a revolution and hallucinogenic drugs in the water supply, Tichy finds himself shot, frozen and thawed out in a future beyond anything he could ever have imagined.