Especially as you are doing a recruiting drive coming out of a slump, and do not have any local competitions available,
Make it Loud!
In addition to one-on-one recruitments, make your build projects something that will bring in more people, then showcase it at a public or whole-school event with many attendees, in a big way.
Finally getting our air cannon out to our football games last year gave us a great inrush of prospective team members. Your circumstances may vary; perhaps a soccer-playing robot, something that climbs a local landmark, or acts like your team mascot will best draw people in. The bottom line is to make something so cool that a lot of people will say "I'd like to be able to build something like that", then show it off and bring those people in for the next round of building.
There was a thread recently on
recruitment, and there have been several over the years on
air cannons,
tote bots, and other neat
off-season projects, many of which make good show-offs.