I initially tried 2 other highly rated calendars and neither worked with Joomla 2.5.1. After much frustration, I purchased a 6 month silver subscription to JEvents 2.1. The calendar worked very well, and support was excellent. I needed images on the calendar, both on the monthly calendar view and event descriptions, so I installed the JEvents File & Image Upload plug-in. That plug-in was great, and I'm using several other plug-ins too. My client loves her calendar. Jevents is a solid and a great product with excellent support. If you need a calendar for Joomla 2.5, use this one.