Abstract: A booster seat for use by a child at an event, e.g., a movie, a theater production, a professional baseball game, etc. The booster seat can be selectively inflated at the intended seat site and, after the event is viewed by the child, can be quickly deflated and folded into an envelope for subsequent ease of carrying and reuse. In one form of the device the inflatable booster seat comprises two separate inflatable chambers. The child has the choice then of being raised either the full intended height of the booster seat (both chambers inflated) or, alternatively, by inflating one or the other chamber, the child can be raised up a portion of the total two-chamber height. An air inlet valve for each chamber is provided to facilitate inflating by the child or the custodial adult then accompanying the child to the event. To facilitate ease of deflation, one or more selectively openable air outlet valves are provided. In a simple version of the device, the air inlet valve is the same as the air outlet valve.