Here are the odd ones out from each group:

1. **a. socializing** - This is an activity involving interaction, while the others can be things or concepts.

2. **b. a comedy** - This is a genre, whereas the others relate to activities or hobbies.

3. **a. magazine** - This is a type of publication, while the others are forms of entertainment or media.

4. **b. harmful** - This is a negative adjective, while the others are activities or creative endeavors.

5. **d. leisure** - This refers to time spent away from work or duties, whereas the others are specific activities or forms of entertainment.