Welcome to the forum!
In spite of your simplistic name, I hope this won't be a one-time visit for you. Especially considering the answer I'm about to give you...
I haven't heard of
Rainlendar before, but it sure looks nice!
The thing is, though, that Android is really,
really intended to work with a Google account; so much so that you can't really do anything useful without one.
![Frown :( :(](/styles/smilies/google/frown.png)
That's a shame, but that's apparently the crummy state of the art on today's pda scene.
So no,
it appears you will have to go through Google.
On the upside, Rainlendar (being iCal compliant) does claim to be able to make use of a Google calendar, although they're a little vague on exactly
how to synchronise with a Google calendar. I did find a link named
Top tip: Sync Rainlendar, Google & Android Phone, but it doesn't say very much either. But hey, it's better than no answer.
For more help, I suggest you ask the Rainlendar community.
Good luck!
![Smile :) :)](/styles/smilies/google/smilie.png)