Which is more dangerous upon contact, series or parallel capacitors? If a pair of capacitors were connected up in series, and an identical pair was connected in parallel which pair would be more dangerous to handle if connected to the same voltage source? 
 A: It all depends. If you charge the capacitors first, and then put them in series, you double the resulting voltage. Hence, if the voltage on just one of them is not dangerous, doubling it may be. On the other hand, if you charge them while they are series or parallel connected, then, as Ruslan explains, you get 4 times the charge if they are in parallel, compared to series. That means they can provide a higher current through your body (depending on the charging voltage). It's the current that causes the danger.
What it amounts to is that there is no general rule. You need to specify the voltage, the capacitance, and how they will be connected before and after the charging process.
A: If you connect identical capacitors in series, resulting capacitance is half of capacitance of each capacitor:
$$C_s=\frac{C_1 C_2}{C_1+C_2}=\frac12C_1$$
If you connect them in parallel, you get twice the capacitance of single capacitor:
$$C_p=C_1+C_2=2C_1$$
Thus, if you try to get shocked in second case, you'll get 4 times more electric energy pushed into your body than in first case (assuming you keep it connected until it almost fully discharges :) ), so parallel connected caps are more dangerous to handle in this case.
A: Two identical capacitors each with capacitance $C$ are charged to the same level.
If you discharge one of these capacitances by touching the electrical contacts, you discharge the capacitance over your body (which we model as having a resistance $R$). Over a timescale $\Delta t = R C$ the electrical energy stored in the capacitance gets dumped in your body. 
Now connect both capacitances in parallel. Compared to the single capacitance case you obtain twice the capacitance and twice the amount of stored energy. Again touch the two contacts. Over a timescale $\Delta t = 2 R C$ twice the electrical energy gets dumped in your body. Hence, the electrical power you are subject to is the same as in the single capacitance case, but the time over which you suffer the power dissipation is twice as long.
Now connect both capacitances in series. Compared to the single capacitance case you obtain half the capacitance and still twice the amount of stored energy. Again touch the two contacts. Over a timescale $\Delta t = \frac{1}{2} R C$ twice the electrical energy gets dumped in your body. Hence, the electrical power you are subject to is four times as high as in the single capacitance case, but the time over which you suffer the power dissipation is half as long. 
Notice that the total energy dissipated in your body by the two capacitances is independent of the circuit chosen (parallel or series). 
Now I am no biologist, and have no relevant medical experience. Yet, I am pretty sure that when forced to undergo an electrical energy dissipation in my body, I would prefer the more gentle experience of a four times slower process.
