You have many options for install a new database but I'm unclear what "without messing their current stuff up" means.

In general, you can create a script that creates the database and all objects or you could have a program submit the queries to the server. Two other options would be to create a backup of an empty (unless you need to keep the reference data) database and restore it or detach the database from your server, make a copy of the files and send them to the client where they can be reattached.

-Mike