Display (or even better choose?) timezone somewhere

[yarikoptic]

Just discovered that datetimes seems to be automagically presented in my local time zone (at least in the Schedule)! Which is awesome! To avoid visitors wondering if the times are in the local to them time zone, I think it might be valuable to explicitly display time zone (even if in just GMT+-offset e.g. GMT+1 or GMT-4) somewhere. Ideally, if it could have been chosen - might be nice as well since it would help people to communicate when to arrive to some event - they could switch time zone to see when it would happen