I wanted to share my frustrating Droid X calendar experiences – I too was experiencing the same issues. I would input an event, it would seemingly save – as verified by the “creating event”, and it would display on my calendar but then, within 10-20 seconds, the entry would disappear! I repeatedly tried inputting the events in different ways – some would stick and remain there but many of them were disappearing. I finally realized that the one thing that the ones that stuck had in common was that I was only using the “What” field – with all of the other entries – if I used the “Who”, “Where” or the “Description” fields, the entry would disappear. So, until I find another calendar app and/or Google updates their calendar app, I will only be using the “What” field – the time fields can also be used as they do not seem to effect whether or not the event disappears. I hope this helps someone.