Best way to detect skee-ball hole

I'm considering making an electronic skee-ball machine. I'm comfortable with all of the programming and physical construction, but what component would be best for detecting when the ball is thrown through a hole? (I know... a pretty important piece!)

My best guess would be a separate flex sensor in each hole to determine the different point values. Seems like push-buttons would be tricky to set it up to be reliable.

the thing I've been considering to add to an airsoft gun of mine, is an IR led and an IR receiver facing eachother on either sides of the barrel, so taht when a BB is fired, itll break the beam between the emitter and receiver for a pulse, and that's how its gonna count. I guess you could try something like that.

Hmm good idea. I have a transmitter & receiver that I haven't even opened yet. Will prob end up doing that then. You think that'd be better than a flex sensor? More reliable?

hmmm well i havent had a chance to play with flex sensors yet so I try to restrict my advice to things I've tried and have worked. What im wondering though, what would be flexing for you to use the flex sensor?

The flex sensor wouldn't be attached to anything (besides wired to the arduino) as the ball passes through the hole it would "pass through" the flex sensor forcing it to bendand trigger a signal for arduino. Only thing I was wondering was if after awhile the flex sensor would become bent and create false positives.

Well actually thats probably a good point, whereas you could mount the IR gear at the base of the hole, after the ball has hit off the walls, so they'll be pretty safe there. But the flex sensor 1 might not get enough of a signal out of some shots because they land better in the hole. And 2 the flex sensor is basically getting beat every time a person shoots, so yeah flex sensors probably wouldnt be too good in the long run.

What if a Grasshopper Drops in! or some kind of other element in the external environment, bingo ball is in! , i will suggest double checking the result, Im thinking how it may happen.

NI$HANT:
What if a Grasshopper Drops in! or some kind of other element in the external environment, bingo ball is in! , i will suggest double checking the result, Im thinking how it may happen.

... well I hope there arent too many insects in your arcade or no kids will come to play.
Double checkign wouldnt be too hard, just have 1 beam straight on acrossed the score hole and another offset so that it takes teh large ball going through and setting off both to cause it to score. I doubt a grasshopper is big enough to cross both streams, maybe a moth or butterfly could, but I doubt theres too many of those in the building. If someone gets a free score, well aren't they lucky.

A micro switch with a long arm.

You might consider having all the switches tied to an interrupt pin and an input pin. The interrupt routine then looks at the inputs to see which switch was tripped and increments the counter for that score.

Hook +5 to the switch and then hook 2 diodes tot he normall oen output, 1 to the interrupt and 1 for the input value.