There are a couple of iterations on a few different sites, but here is what I use:
<p class=”gce-list-event gce-tooltip-event”>[event-title]</p>
[if-all-day]<p>All day</p>[/if-all-day]
[if-not-all-day]
[start-time] to [end-time]
[/if-not-all-day]
[if-location] Location: [location][/if-location]
<p>
</p>
Here is what it looks like