Just give it a try for a week and see if you find value in the methodology.
Secondly, there are many Agile methodologies. The first step should be to sit down as a team and work through the manifesto, identifying areas for improvement.
Only once that's done is there any point in thinking about choosing a methodology.
The point was to encourage our fellow HN member to be open minded and try it for a short period of time. From there he can determine if the change has begun to yield any value or not.
Suggesting a team 'try a methodology for a week' is inviting a train-wreck.
Let's say the OP decides to adopt Extreme Programming.
How long would you say that a team with zero experience in that methodology would take to get to the point where they're practising it well enough to perform a useful evaluation of the consequences?