I've only read some of the answers, so I'll probably repeat someone.
If they're hungry, they'll eat. If they're not hungry, they won't. Bearing that in mind. Start setting the timer for 30 minutes and TELL them that breakfast is over when the timer goes off in 30 minutes. What they choose not to eat, it gets pitched or saved for the next meal time.
Someone mentioned snacking. Make sure you start having set meal times. Breakfast at 7, snack at 9, lunch at noon, snack again around 3, then supper at 6. Of course you can make up your own times, but I would keep 2-3 hours between every meal.
As for the playing with their food, discourage it, but time outs really aren't helping I can only assume. The Love and Logic program would tell you to tell them that if you see them eating nicely that you will let them eat their food. Likewise, it would also tell you that if you don't want them playing with their food or getting up from the table during the meal.... Say "oh you must be done" and put the food up. I do encourage keeping them at the table (booster seats) until everyone is finished. (teaches respect if nothing else).
If breakfast time is the hardest time to get them to eat, they might not be hungry yet. Sometimes it does take time to finish waking up and for our tummies to be ready for food again.
Another incentive of course is making the rule, no seconds or desert unless you finish the food on your plate. (but make sure you're feeding them child sized portions, which I'm sure you already do.)