upload file and use cache...

Hi, is there something I can use to upload a file to filesystem just
for a temporary time... I just need to execute a ruby script on the
file and then I can delete it... Is there a way to just upload it to
cache and then clear it? I don't need database to store all the
informations...

Thanks in advance

I forgot to mention that the file need to be uploaded for an URL and
not from your own desktop...