Having letter shirts (you can get sticked t-shirts, jerseys, hockey shirts, sweat shirts, or even jackets) is something that's fairly common amoung most GLOs, and is a great traditional item that all members should wear. Many chapters present newly initated members with their first letter shirt, usually paid for and presented by their Big Brother/Sister (as the case may be).
Start a new tradition of having everyone get letter shirts, choose a day of the week in which everyone wear them, encourage them being worn at recruitment events, fellowship events, etc.
Also, everyone should know everyones names. Part of most pledge programs are things to get the pledges to met all the members (gather signatures, questions to ask the members, etc)
Fellowship event need not be major. Here are some ideas.
* after meeting 'dinners' (can be at a nearby resteraunt, say a Denny's or the like).
* once a month 'birthday parties' (get together each month to celebrate everyone's birthday in that month. Again, can be something simple).
* bowling event
* pool party (either swimming pool or billiards
). Does a member or an advisor have a pool you could use?
* picnic/cook out at local park
* holiday party (say around thanksgiving before everyone leaves, around xmas, etc)
* dinner & a movie
* end of year awards banquet
Several of the above things can be done following a service project. So you could do a saturday morning service project, followed by a fellowship event. Say you do a service event at a local park, followed by a cook out.
Hope this helps.