Take a train ride: Carlsbad has a long tradition of being a train stop on the line between Los Angeles and San Diego. You can imagine what it was like when the country was still wild all around. You'd stop in Carlsbad, a small outpost on the coast, spend the night at a Victorian hotel by the alkaline springs and spend your days laying on the beach. You can visit the original train station, built in 1887, which sits at its original trackside location on Elm Avenue just west of State Street. It's a forgotten piece of California history. 
You'll want to catch a train to downtown San Diego to see the most beautiful train ride in the country. The tracks will take you through Del Mar where you will be right on the beach. If you were any closer to the Pacific you'd be in the water. It's a spectacular ride and one that would never be built today because the land it traverses is just too valuable. The right time of year you can spot Gray and Humpback whales from the train. Dolphins are frequently spotted when the water warms up in spring and summer.  

Visit the alkaline springs: Carlsbad exists primarily because of the unique water that flows beneath the town.  You can't really say you've been to Carlsbad unless you have tasted the water that made this town a destination. 

Carlsbad Mineral Water was discovered in 1882 by Capt. John Frazier when he drilled 
a well for his farm near the beach. The alkaline mineral water cured a stomach ailment 
from which Capt. Frazier had suffered for years. Intrigued, he sent samples of the water 
to two independent testing laboratories in New York and Chicago. The results showed 
his water was chemically very similar to the healing spring mineral waters found in a  
famous European spa resort that was at that time called Carlsbad, in Bohemia (Today, 
the city is Karlovy Vary, Czech Republic, and is still famous for its therapeutic spas.) 

One of California’s real estate booms was happening at the time, and Capt. Frazier  
platted his farm for a city  that he called Carlsbad. He also started bottling his water  
and selling it across the nation as (The American) Carlsbad Mineral Water. He built a 
huge Victorian hotel beside his original well, and people came from all over  the world 
and included at least two U.S. presidents enjoying the alkaline mineral water for 
drinking and for bathing, just as they would in the European Carlsbad. 

Nerd Comedy Night: This Carlsbad tradition happens every Friday night at El Tejate, just outside the Carlsbad village.  It's a comedy night for people that are nerds at heart. The show is broken up into two parts. A couple family-friendly comedians open the show often interacting with the crowd as they entertain with comedy bits. Part two is the Nerd Olympics. It's a live game show similar to Jeopardy but the questions are ones only a nerd would know the answer. The contestants are volunteers from the audience so if this sounds like your cup of tea you can be a contestant in the Nerd Olympics. Just raise your hand when they ask for volunteers.