Worked great in WP 2.8, skipped interim 2.9 builds and upgraded to 2.9.2
Now when on the Calendar page, I click the date to create a new event and the yellow entry form pops up but the time drop-down offers only 12:00am - 1:55am in 5 min increments.
Additionally, the icon in the Post WYSIWYG interface opens a blank window.