I'll give you the same pitch I gave my players when we first started playing DL...
Dragonlance is a high-fantasy, epic world with a rich history and a very specific theme. The theme around stories set on Krynn (the world that Dragonlance takes place in) centers on groups of ordinary people who grow into heroes who do extraordinary things. Most stories that take place in Dragonlance have to do with strong moral elements of good vs. evil, so parties tend to be good aligned (though, there are reasons for evil characters).
The Gods of Krynn play very important roles in the world, constantly maneuvering to gain dominance (for the Gods of Evil), to protect their lands and peoples (for the Gods of Good), or to maintain the balance (for the Gods of Neutrality). This is reflected in the three major “laws” that rule the Gods of Krynn:
Good Redeems its own
Evil turns upon itself
The balance must always be maintained
Thousands of years ago, the Queen of Dragons, the 5 headed Dragon Goddess Takhisis, broke the balance. Her brood, the chromatic dragons, wreaked havoc on Ansalon (the main continent that most Dragonlance stories take place on). The Gods of Light were losing, until a lowly knight known as Huma gained the trust of the Metallic Dragons and forged the mighty Dragonlance, a weapon that turned the tide of the great Dragon War. With this weapon, Huma pierced the breast of the 5 headed dragon, forcing Takhisis to withdraw from the world along with her brood. The metallic dragons, to maintain the balance, also withdrew. And dragons became the thing of myth and legend.
Just over 350 years ago, a great civilization sprawled across the eastern portion of Ansalon. This nation was known as Istar, and it was ruled over by the Kingpriest of Istar, a man devoted to the God of Light known as Paladine (also known as the Platinum Dragon). He began eradicating the evil races of Krynn, killing off Ogres and Goblins, forcing many of the “impure” races (like Dwarves, Gnomes and Kender) into hiding, and forcing a war against the orders of Sorcery. As the Kingpriest’s laws became more and more forceful and sterile, priests began to lose their powers. Those who were still able to heal began disappearing. The Kingpriest, thinking that it was some evil plot, demanded that the Gods eradicate all evil from the world.
The Gods answered in a most spectacular fashion.
Because the balance had swayed too far toward good, and because the Kingpriest was so arrogant that he felt he was equal to the Gods and that he could demand anything of them, the Gods retaliated. What was described as a fiery mountain fell from the sky, striking the nation of Istar, sinking it beneath the sea. What was left was a swirling vortex known as the Maelstrom in the center of a great sea known as the Blood Sea of Istar (the water here is as red as blood).
This was known as the Cataclysm. All time from this point forward is recorded using A.C. (After Cataclysm).
The face of Ansalon was changed forever. War, sickness, and death ravaged the land. The Gods of Krynn left the people of Ansalon to their own devices…not that the people of the world would pray to them, anyway…not after the death and destruction of the Cataclysm.
The world descended into savagery and barbarism.