Use 3 drop down times
Instead of the one drop down list with the half hour increments, use one drop down list for the hour, another for the minutes in 5 minute increments, and add another for the am or pm. It's a royal pain to have to try and override your time settings to get it to read 45 or 15.
Diane Fahlbusch commented
I am certain I am not the only one who has events starting or ending in th quarter hour.