you would have javascript tweak the custom island ( manipulate the DOM ) after the fact based upon getTimezoneOffset ( user browser supplied ). note, you'll have jQuery loaded by the board, so all the $('select me') goodness will be there
i misunderstood that you had a precompiled CI, but the idea still translates ( i think )
you may have to modify the event island to not be so specific (ie: just do it in GMT), if you have offsets over 12hrs different. that way 'today' would be easier to modify based upon who's browsing. then the jQuery would do it's magic
Anyway.. we won't be doing anything with calendar ( major ) until a later release