Synonyms for "Exciting":
General:
* Thrilling
* Stimulating
* Electrifying
* Arousing
* Invigorating
* Captivating
* Intriguing
* Enthralling
* Engrossing
* Riveting
* Spellbinding
* Fascinating
* Alluring
* Appealing
* Dazzling
* Breathtaking
More specific:
* For events:
* Dramatic
* Spectacular
* Thrilling
* Adrenalin-pumping
* Heart-stopping
* For people:
* Energetic
* Vivacious
* Animated
* Dynamic
* Passionate
* For ideas:
* Innovative
* Groundbreaking
* Novel
* Visionary
* Cutting-edge
* For objects:
* Stunning
* Gorgeous
* Striking
* Magnificent
* Breathtaking
Informal:
* Awesome
* Cool
* Rad
* Epic
* Killer
The best synonym for "exciting" will depend on the specific context and the desired tone.