Paintball

Particularly proud of this post in a paintball forum:

Alternatively, you could do it while walking in the streets. Every time you come to a corner stand behind it, and peek out, pretending to hold your marker.

Several levels to this.

• Noob Level: Everyone coming from the opposite direction gives you weird stares. Practice more.
• Ninja Level: People do not notice you standing there peeking out. You're getting there
• Godlike Level: People fall over every time you peek out and squeeze off a few imaginary rounds. Wow.
• Paintballer Level: People run and dive for the nearest cover and do their own snapshooting at you. You get involved in a fullblown one on one and WIN. After loosing, they don't know why they just did that. On asking, they claim it was something about your posture.