This is basically the first script I wrote for Transformice.
The script allows you to fly.

--[[
Description: Fly hack ported to lua.
Use [SPACEBAR] to fly!
Author: Jordynl.
]]--

function eventNewPlayer(playerName)
    tfm.exec.bindKeyboard(playerName,32,true)
end

function eventKeyboard(playerName, keyCode, True, x, y)
    if x ~= 0 and y ~= 0 then
        tfm.exec.movePlayer(playerName, playerName.x, playerName.y, false, 0, -50, off)
    end
end

for k,v in pairs(tfm.get.room.playerList) do
    eventNewPlayer(k)
end