'though' is used when two pieces of information are different. It shows contrast between two ideas. For example:
"We're going to have chocolate cake for your birthday!"
"I don't like chocolate, though."
This is a pretty informal usage, and emphasizes the person's dislike of chocolate.
"Though I don't like chocolate, my birthday cake was delicious."
Because you used 'chocolate' in the first clause, you don't need to mention that the cake was chocolate in the second. 'though' ties the sentences together.
"He was an intelligent, though lazy, student until he went to grad school."
Here again, 'intelligent' and 'lazy' are contrasting statements about the same person.