When can I take money from my 401(k) without penalty?

Under certain circumstances yes. Over a certain age, yes. This site has details on those circumstances and the age:

http://wps.fidelity.com/401k/about/with.htm

When you retire. 65 - I think.

Ummmm - no, pitbull. That is not correct. That is when you are entitled to any match that was put in and earnings. You can't take the money out then. That just means you own it at that point. The tax lawys dictate a penalty and taxes for early withdrawal.

Think it's age 59 1/2 but it could be 60 .

1) Age 59.5

2) Dead (.....I don't recommend this one)

3) Disabled (....this one either)

4) Age 55 and permanently separated from service

There is a reason the it is called a retirement account. It is for your retirement. The 10% is incentive to keep it in there.

my sister was laid off from her job and she was over 49 1/2 at that time so she was able to withdraw her entire account instead of rolling it over into an IRA.

When you are fully vested. Usually about 3-5 years depending on your company's policy.