Not sure what you want. You want to combine data by day. How is the epidemiological curve?
library(lubridate)
library(plyr)
library(ggplot2)
dat = read.table(header=TRUE, text='Date Event
January-29-2014, 1
January-29-2014, 0
January-29-2014, 1
January-29-2014, 1
January-30-2014, 0 ')
dat$Date = mdy(dat$Date)
agg = ddply(dat, 'Date', summarise, Events = sum(Event))
ggplot(data=agg, aes(x = Date, y = Events)) + geom_bar(stat='identity') + scale_x_datetime(expand=c(1,0))
Output:

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