Just the gist (for small children and others with tiny attention spans):
God gave Solomon the gift of wisdom because Solomon was wise enough to ask for it. The kingdom of Israel was at its largest and most peaceful under King Solomon. He built God a glorious temple, wrote a bunch of wise literature and became famous worldwide for his smarts and wealth. Unfortunately, at the end of his life, he turned from God and started worshipping the gods of his many pagan wives.
For those that can handle just a bit more:
David and Bathsheba had a baby named Solomon and it was he that God chose as David’s heir. Before David died, he told Solomon to always be faithful to God and he would be all right. (1 Kings 2)
God asked Solomon if there was anything he’d like, anything at all. Solomon said, “Give your servant an understanding mind to govern your people, that I may discern between good and evil.” (1 Kings 3:9). Which is Bible talk for wisdom. God was impressed that Solomon asked for wisdom instead of riches, honor or indoor plumbing so he gave him all of it (well, not the indoor plumbing).
Solomon put his wisdom to work judging maternity cases (his most famous case isn’t really Christmas talk but can be found at 1 Kings 3:16) and writing a bunch of wise literature for the Bible like Proverbs, Ecclesiastes and Song of Solomon. It’s also rumored that he wrote as Dear Abby for a brief time. Reports of his wisdom traveled so far that the Queen of Sheba came to visit to see if what she’d heard was true. She was very impressed and gave him a bunch of spices which was like getting a five-star review back then. (1 Kings 10:1-10)
Solomon also set out to do what King David wanted to do but that God said would be David’s son’s job – He built a glorious temple for God. After Solomon’s very eloquent prayer of dedication of the temple, God packed up his presence from the little tabernacle in the tent and His Glory descended on the temple. God told Solomon that the temple looked great, but that if Solomon ever ended up worshipping false gods, the people of Israel would be cut off from the land (which is Bible talk for exiled) and the temple would crumble into ruin (which is Bible talk for uncontrolled demolition). (1 Kings 9:1-9)
As happens so many times in biblical history with the people God deals with, Solomon did not heed God’s words. Instead of being content with reigning over the ginormous kingdom his father had fought for and won, having untold wealth, a thousand wives, being the world’s wisest man and having God Himself dwell in his capital city, he fell away from God and started worshipping the pagan gods of his wives. (1 Kings 11)
However, since God was so fond of Solomon’s father, the curse on Israel would not come about until after the death of Solomon.