Dealing with a High-Energy Lab in the City

Hey everyone, I could really use some advice on managing my 2-year-old Labrador Retriever, Ollie, in the city. He has so much energy and I'm struggling to keep up with his exercise needs while juggling work and life in Seattle. Any tips on how to keep him entertained and tired out without spending hours at the dog park every day? Thanks in advance for any suggestions!