My job has an event each year that is mandatory for all employees to work and attend, but we do not get paid. If we don't show up, then we are written up. Isn't there some law against this? If so, where can I find the information so that I can make a call and complaint about the situation?

If you are an exempt employee, you can be required to attend some event and receive no extra pay.

Non-exempts, however, must be paid for all hours worked.

US Dept of Labor Fact Sheet (http://www.dol.gov/esa/regs/compliance/whd/whdfs22.htm)

Lectures, Meetings and Training Programs: Attendance at lectures, meetings, training programs and similar activities need not be counted as working time only if four criteria are met, namely: it is outside normal hours, it is voluntary, not job related, and no other work is concurrently performed.

Since the event is not voluntary, it does not meet the criteria above, so the time counts as hours worked (even if no "work" is done). If attendance at the event puts an employee over 40 hours, overtime must be paid, too.

And you would file the claim for unpaid wages with the state Dept. of Labor. If you really are in Texas, that's the Texas Workforce Commission.