Usually the colored contact lenses will help you get the color you want for the eyes. And the red eyes will show the unhealthy symptom for the eyes. You could use the eyes for a long time before the computer and let them get tired. Then your eyes will get red. If you stay up late, your eyes may have the bloodshot which could also make your eyes get red.
It's not good for your eyes. You'd better not do so.
But there are some ways to achieve that.
1. rub your eyes. Really bad for your eyes.
2. Get smoke into your eyes.
3. Stay up late and don't sleep, see your eyes the other day
4. Drip some mint or pepper sauce into your eyes. This is really uncomfortable.
P.S. All these are really harmful for your eyes!
Well, that is a very weird question. But as a matter of fact, there are simply no good ways to do that, except you try to cry a lot. In the meantime, you could try to get a pair of special contact lenses for fun, which could make you have a pair of red eyes and become scary!! Just try to take care of your eye health and don't do anything stupid! Otherwise, infections could happen.