I love teaching the 2nd conditional. It's a great deal of fun! There are several activities, one of which my students seem to enjoy the most. It's the "What if . . ." Game.
 Grammar Practice [10 minutes]
Handout slips of paper, five per student. Have the students write down at least 5 questions of the type,
What would you do if . . . ?
If you were . . . , what would you do?
If you had . . . , what would you do?
What if . . . ? What would you do?
Note 1, If it's a big class, or a low level class, place the students in groups of four. Have each pair work on 5 questions.
Note 2, give the students a few examples to work from; tell the students that their question can be serious or silly.
 Oral Practice [15 minutes]
Pair the students up, and have them ask their questions in turn. (See Option #2 below)
Functional Language [25 minutes -set up, play, cool down]
Collect all the slips of papers.
Divide the class into two teams.
Have one student from each team come to the front of the class (podium).
Tell the class they're going to participate in a game show.
Select one of the questions from the stack of slips and read it aloud.
Optional: a bell
The first person to (hit the bell and) answer correctly wins a point for their team.
The person who doesn't answer fast enough or who answers incorrectly gets to choose and read the next question.
The game ends when every student has had a chance to participate in the game show.
Note, if it's a big class, you could always divide the class into four teams, and base points on the "best" or "funniest" or "most interesting" answer.
Option #2: Move the desks to the back of the room; place the chairs in two long rows, so that the students are seated facing each other. Each facing pair is a team. Use a timer, set it for two minutes. When you say "Go! or "Start", the students in the right-hand row read a question from their list, and the students directly opposite, in the left-hand row, provide their answer. Once an answer is given, the students in the left-hand row ask a question from their list, and so on until the two minute timer goes off. When that happens, all the students in the right-hand row stand up and move one seat up, and the timer is set once again. Note, the person at the end of the row doesn't have a seat to move to, so s/he walks back to the beginning of the row and takes that vacated seat.
My students LOVE that activity; they say they get a great deal of speaking practice in.
All the best,