This is my favorite font, Lavanderia, and I'd love to download it but it just won't install into Font Book. I've tried all three versions of it, but it just won't work. Is it because they are OTF files? If so, is there anywhere to find a TTF version of it? And if not, can I have some help downloading it? Thank you!

You can convert it to TTF here: http://www.freefontconverter.com/

Thank you for the help, but when I uploaded it it said '500 internal server error'.

Hmm...that's weird. There are lots of other ones like these:
http://www.files-conversion.com/font-converter.php
http://everythingfonts.com/otf-to-ttf

Alright, it's downloaded now but isn't showing up in Pages.

It's showing up in Photoshop, maybe it's just taking a while to refresh the fonts on Pages. Thank you for your help!

I Have a lot of fonts a folder full about 1500 fonts . and the problem Is that I can't decide who to use

You're welcome!