I have added a neat feature to the Gallery Tour HUD. There is a new button named "Events" on the HUD menu that gives you two choices: Current event info in progress, or upcoming events on the current sim. Only Arts & Culture events are searched. Also, when someone teleports to a new location, the HUD will automatically look up event information, and if there are any upcoming events in the local sim, they will be shown to the HUD user! That way they will be more aware of any advertised events at your gallery if they land there with the HUD on (or anywhere else on the sim). Give it a go and let me know what you think - you can query the normal events listings for Arts & Culture, find something happening soon, and just teleport to that event and see how the HUD notifies you of that event.
This was pretty tough to implement since there is no official interface to the event listings from an LSL script. Please consider this an experimental feature.
Please be sure to take a moment and stick your upcoming gallery events in the LL event listings when you schedule an event so that they show up for HUD users. Hopefully this will help make people more aware of upcoming gallery events as they travel around with the tour HUD!