I've taken expired aspirin before without any health effects and the expired aspirin worked just fine for what I needed it for.
The only thing that would really happen to you if you take expired aspirin is that the aspirin may not work on the pain or other problem you're having as fast.
I have never had a problem for many years taking expired aspirin and I once asked my doctor about it after I accidentally took some expired aspirin without realizing it.
The doctor said that there really was no harm in taking the expired aspirin but he said that the expired aspirin sometimes loses it's effectiveness overtime after it expires but there's no health danger taking the expired aspirin.