Read original post by Deyan Ginev at Telerik Blogs
It is a common scenario when we would like to limit the selectable values in a time or date picker control. Normally we would do this by setting an allowed date-time range but a more sophisticated case is when we also want to filter out some selection possibilities and allow only specific ones. Imagine an application that provides the end-user with the possibility to create reminders that can only happen in time intervals of 15 minutes:
3:00 AM, 3:15 AM, 3:30 AM...