Are you using the Calendar or the Scheduler? There are several options:
1. Increase CellWidth (Scheduler)/CellHeight (Calendar). In the Scheduler, you can also increase EventHeight.
2. Add a Bubble that will display the full event details on hover.
3. On the client side, you can handle onEventMouseOver and onEventMouseOut to display the full details in another way (a special area above/below the control). These events are available in the Scheduler and need to be added using the client-side JS object.