Lion:
Check with professional organizations, like ASCE, ACEC or NSPE, etc., or various materials organizations involved in research and code writing, like AISC, ACI, PCI, AWS. They are all always looking for new blood, and of course, you tend to get out of it what you are willing to put into it, the old std. saw. Look up their committees and the list of committee members, you might even know some of them. Call the organization and/or chairperson, or any of the members, most of them can’t bite you over the phone. Consider an area of engineering or business which your own office is interested in, and get them to help defray your costs and subsidize your time, because it makes them better or look good to have you involved.
Certainly we want young engineers, we need you to do all the leg work, while we take the credit, as the older guys on the committee. What you have shown here, on this forum, would likely quickly make you valuable member of most any professional organization or committee. Like Rowing suggested pick something you are interested in, and then an active committee, and talk to a few of the members to see what’s going on. It might take a couple tries to find a subject fit, and a group of people you like working, but it’s well worth the effort if you’ve got the time and energy. Looks good on your CV too.
Good Luck