
The Balaclava is the prized item for deckworkers--follow the appropriate Topic link to learn how to make one!
A spaghetti boil is easy for any group, and if you approach a large supermarket, often they will donate papergoods, pasta and prepared sauce, and maybe more. We suggest that you not charge a fixed price but explain that this benefits a Mission to Seafarers. We'll supply publicity materials. Make the cost of the meal a free-will offering.
Look around for open mic nights in your area, and leave a flyer asking for performers to show up and do 3-4 songs or 15 minutes, whichever comes first. Serve coffee, tea, snacks. A small cover charge or again, a free-will offering should be asked. This is easy to do, a lot of fun, and it can be done once a month as an outreach minsitry to those who want to go out for live music but don't want to sit at a bar.
This makes a great internal fellowship event, but it also makes a really great outreach. You may make your coffeehouse just for Christian music, but if you'd like to involve new friends, make it folk and poetry (but let them know that you are a Church, and judicious selection of material is called for!).
NESM has a very small staff who sometimes can come out to your Church or to your group to speak about Maritime Missions and about missions in general. This works best if you're not too far from Boston.