I don't know about everyone else but I do a lot of pen and paper prototyping. It usually takes a few hours but with some simple rules I can set up a similiar version as a board game. I used dice, grid paper, ruler, flash cards and a pencil, with these I can set up all sorts of ways to flesh out an idea or see if it is fun.
For example I layed out a game called Bomb Voyage (working title) into a board game in about 2 1/2 hours.
The concept was simple the player picked a character to play as, each character had to find specific items relating to them on a cruise ship before it sank. A bomb was planted on board hence the title.
Say you pick average joe as your character, you would need to find his daughter, wife, and dog.
To layout the map I just drew different levels of the ship on grid paper, movement was handled by dice and a movement modifier based on your character.
I had a deck of flash cards with items on them that you would draw after your turn was over to represent finding them.
I used monopoly pieces to identify level obstacles such as fire, broken beams, people and etc. each item gave you a bonus to get past obstacles but you could only hold so many at one time.
I used Dice rolls to see if the player cleared the obstacle or not, varying levels of the roll resulted in different effects e.x. If a panicked mob is rushing down your corridor you need a 5 to dodge them. Adding any modifiers to your dice roll the final result had to be >=5. If you rolled a 1-3 you were stunned and lost a turn, a 4 you couldn't move but you were safe and a 5 or greater you bypassed the crowd and continued your turn.
The time limit on the level was represented by a set limit of turns before the ship sank. It took a few plays to whitle this to an appropriate number. Every 10 turns a secondary explosion woud go off and that would randomly generate new obstacles on the map. Handled that by just tossing tokens onto the map.
I tested out a lot of things but it even let me realise how many players should be in one game at a time, so I knew the minimum of differing characters I had to make.
Then it all fit neatly in a box and I could bring it anywhere to let people test it out and give feedback.
This might seem like it went off topic a bit, I just wanted to share some ideas on how you can represent game actions through a board game and somewhat of how it at least helps me decide which project I'm going to follow through with.