Afterwork event.

Today I am going to an "afterwork", Ocasionally I go out with my colleagues but without a predefined plan, we only want to talk in a different place than the office in order to be in touch or to touch base, but in this ocasion we are going to be in an "afterwork" event, a place created specially for this purpose. Lately this kind of events have been expanding very fast in my city, now it´s the time to test if they´re a good idea or they´re only another transitory trend. Tomorrow I'll tell you my opinion.

Bye.

Today I am going out after work to an "afterwork". (I have never heard of an 'afterwork' but sounds like they are in your city!). Ocasionally I go out with my colleagues but without a predefined plan. We only want to talk in a different place other than the office in order to be in touch or to touch base (you wouldn't really say 'touch base' if you were catching up with colleagues/friends socially, you would say 'catch up'). On this ocasion we are going to be in an "afterwork" event which is a place created specially for this purpose. Lately these kinds of events have been expanding very fast in my city. Now it´s the time to test if they're a good idea or they´re only another transitory trend. Tomorrow I'll tell you my opinion.

Nice, try to keep your sentences a bit shorter.